Electromagnetic flow meter

ABSTRACT

An electromagnetic flow meter provided with a resin lining portion in which resin is lined in a measuring pipe by pressure molding, including the measuring pipe to flow liquid to be measured, a lining locking frame provided in the measuring pipe composed of a cylindrical plate with openings and a plurality of divided belt-like ring plates, and the resin lining portion formed by embedding the lining locking frame. Here, in case of pressure molding the resin lining portion, the resin to be lined can be filled easily in gaps between the measuring pipe and the lining locking frame via gaps formed by a first gap provided between the inner face of the measuring pipe and the outer circumference face of the cylindrical plate with openings and second gaps of the adjacent divided belt-like ring plates in the outer circumference direction of the measuring pipe.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2009-121219, filed on May 19,2009; the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electromagnetic flow meter, and moreparticularly to an electromagnetic flow meter provided with a measuringpipe to flow fluid to be measured in which a resin lining portion islined by pressure molding.

2. Description of the Background

An electromagnetic flow meter generates a magnetic field in a measuringpipe by flowing current in a coil, and detects a magnitude of anelectromotive force generated according to the dielectric constant ofthe fluid flowing in the magnetic field so as to measure a flow rate. Atthe inner face of the measuring pipe of such an electromagnetic flowmeter, the lining is performed for insulation, by resin such as fluorinecontained resin and polyurethane resin and so on.

As a resin lining method of the electromagnetic flow meter, a methodcalled transfer molding is known, for example. In this method, a die isfitted on both ends and an inner portion of the measuring pipe, andthese are heated to an approximately melting point of the resin to belined, and then the melted resin is pressurized and inpoured in gapsbetween the measuring pipe and the die.

In addition, as another resin lining method, a method called moldforming or injection molding is known. In this method, a die is fittedon both ends and an inner portion of the measuring pipe, and these areheated but not to an approximately melting point of the resin to belined, and then the melted resin is pressurized and inpoured in gapsbetween the measuring pipe and the die.

Further, as another resin lining method, a method is known further inwhich a die is fitted on both ends and an inner portion of the measuringpipe, pellets of the resin to be lined are preliminarily inserted ingaps between the measuring pipe and the die, these are heated till theresin pellets to be lined melt in the gaps between the measuring pipeand the die, and then the resin is pressurized and molded.

In addition, hereinafter, these three molding methods are calledgenerally as pressure molding methods.

In a conventional electromagnetic flow meter with a measuring pipe inwhich resin lining is performed, so as to prevent a resin lining portionfrom peeling off from the measuring pipe in such a case that the insideof the measuring pipe becomes at a negative pressure for the ambientair, a technique is known that the resin is inpoured for lining after acylindrical plate with openings is pasted on the inner face of themeasuring pipe as a reinforcing member.

A following forming method is disclosed (refer to Patent Document 1, forexample). That is, a forming method is disclosed in which a tubular bodywith openings is formed by winding a plate with openings as areinforcing member to be embedded in the resin in a cylindrical shape soas to be inserted in the measuring pipe, and then spacers are fitted atthe outer circumference face of the tubular body with openings, andafter the tubular body with openings is inserted and fitted in themeasuring pipe, the measuring pipe is coated with resin by mold forming.In the forming method, before mold forming the tubular body withopenings, while contacting both ends of the plate with openings tightlyin the circumference direction, the plate with openings is displaced inthe axis line direction so as to increase the diameter of the tubularbody with openings till the outer circumference faces of the spacerscontact tightly with the inner circumference face of the measuring pipeto form the tubular body with openings.

In addition, as a technique to prevent a resin lining portion frompeeling off from a measuring pipe without using a reinforcing member, atechnique is known that dovetail grooves are formed in circumferenceshapes at the inner face of the measuring pipe, or dovetail grooves areformed at the inner face of the measuring pipe in the axis direction,and the resin is inpoured for lining (refer to Patent Document 2, forexample).

Patent Document 1: Japanese Patent Publication (Kokoku) PH3-124

Patent Document 2: Japanese Utility Model Publication (Kokoku)US61-16493

A forming method of a resin lining of a conventional electromagneticflow meter will be described with reference to FIGS. 8A, 8B, 8C. FIG. 8Ais a diagram to explain a lining structure, and FIG. 8B is a perspectiveview showing an appearance of a lining locking frame 27 to prevent thelining from peeling off.

A side sectional view of an upper portion from a center of a pipe axisof a measuring pipe 1 in FIG. 8A indicates a state before resin lining.The measuring pipe 1 to flow fluid to be measured is composed of a pipebody 1 a, a pair of flanges 1 b provided at the end portions of the pipebody 1 a, and a pair of internal substance storing boards 1 c to storethe loading substance such as a coil and so on, which are welded on theouter circumference of the pipe body 1 a symmetrically to the center ofthe pipe axis in the pipe axis direction of the pipe body 1 a.

In addition, a side sectional view of a lower portion from the center ofthe pipe axis in FIG. 8A indicates a state after resin lining to themeasuring pipe 1. A resin lining portion 3 to be lined at the inner wallof the measuring pipe is made of an insulating material such as fluorinecontained resin and polyurethane resin and so on. In addition, thelining locking frame 27 formed in a cylinder shape of a thin steel platewith a plurality of openings bored is embedded by mold forming.

The lining locking frame 27 is composed of a cylindrical plate withopenings 2 a and a plurality of belt-like ring plate 2 b 2 welded aroundthe outer circumference of the cylindrical plate with openings 2 a.

The lining locking frame 27 is loaded in the measuring pipe 1 so as tocontact the outer face with the inner face of the measuring pipe 1.

Then, a lining molding die not shown is fitted around the measuring pipe1 loaded with the lining locking frame 27. And the resin lining materialis pressure injected from an end of the measuring pipe 1 between thelining molding die and the inner face of the measuring pipe 1. By this,the resin lining material is filled around the lining locking frame 27via a lot of openings A of the lining locking frame 27, so that theresin lining portion 3 is formed by embedding the lining locking frame27.

The resin lining portion 3 formed as described above is provided with astructure in which the resin lining portion 3 is locked by the lininglocking frame 27 and is enforced, and in addition, the lining portion 3is made possible to outstand the change in negative pressure andexternal pressure and is not peeled off easily from the measuring pipe1.

Next, a problem of forming the resin lining portion 3 of theconventional electromagnetic flow meter constructed as described abovewill described with reference to FIG. 8C.

Regarding the lining locking frame 27, the belt-like ring plates 2 b 2are contacted with, and a few of the belt-like ring plates 2 b 2 arespot welded to the inner circumference face of the measuring pipe 1. Inthis case, there is a problem that the diameter of the cylindricalplates with openings 2 a made of the thin steel plate and the innerdiameter of the measuring pipe 1 are contacted within a prescribedtolerance and are welded so that the cylindrical plates with openings 2a does not float from the inner face of the measuring pipe 1. Regardingthis problem, a solving method is disclosed in Patent Document 1, forexample.

But in the forming method of the resin lining disclosed in PatentDocument 1, there is a problem as described below.

A radial thickness of the resin lining portion 3 is set by providing aprescribed gap x between the cylindrical plate with openings 2 a and themeasuring pipe 1 at the circumference of the lining locking frame 27 asshown in FIG. 8C. Regarding the gap x, the radial thickness t in thedirection perpendicular to the pipe axis is set by a plate thickness tof the belt-like ring plates 2 b 2, for example.

The resin lining portion 3 is formed mainly by pressure injecting themelted lining resin in the space partitioned by the belt-like ringplates 2 b 2 from a lot of the openings A of the cylindrical plate withopenings 2 a. In this time, in order to keep the quality of a uniformstrength at each portion of the resin lining portion 3, it is requiredto form the resin lining portion 3 without including the air bubbles andwithout remaining residual stress in the lining resin itself caused bythe non-uniformity of the pressure at the pressing places.

For the reason, in case of the lining locking frame with a constructiondisclosed in Patent Document 1, there was a problem that a high levelmolding technique such as transfer molding or injection molding isrequired to heat the measuring pipe and the die for mold forming, and inaddition, to inpour the lining resin by pressure melting at not lessthan the prescribed temperature.

In addition, in forming the resin lining according to theelectromagnetic flow meter of above-described Patent Document 2, atechnique is disclosed to perform lining by trenching a plurality ofdovetail grooves extending in the direction of the entire length of thepipe axis along the circumference direction at the inner circumferenceface of the measuring pipe, so as to prevent the lining resin frompeeling off from the measuring pipe.

However, so as to provide a plurality of such dovetail grooves, there isa problem that though it is possible to fabricate the dovetail groovesat the end portions of the measuring pipe, it is difficult to fabricatethe dovetail grooves at the central portion of the measuring pipe. Inaddition, as the lining resin is to be inpoured at the acute portions ofthe dovetail grooves without including air bubbles, there is a problemafter all that a high level molding technique such as transfer moldingor injection molding is required.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide anelectromagnetic flow meter which can form a resin lining portion easilywithout generating air bubbles and residual stress in the lining resin,and without using a high level molding technique such as transfermolding or injection molding.

According to an aspect of the present invention, there is provided anelectromagnetic flow meter provided with a lining portion in which resinis lined in a measuring pipe by pressure molding, including themeasuring pipe to flow liquid to be measured, a lining locking frameprovided in the measuring pipe, composed of a cylindrical plate withopenings and a plurality of divided belt-like ring plates, and the resinlining portion formed by embedding the lining locking frame. Thecylindrical plate with openings is formed by facing both end faces of abelt-like plate with openings with a prescribed length in acircumference direction of the measuring pipe so that the belt-likeplate with openings becomes a cylindrical shape concentric with themeasuring pipe. Each of the divided belt-like ring plates is composed ofa plurality of belt-like plates with a prescribed length and is madering-like around the outer circumference of the cylindrical plate withopenings by providing second gaps between the belt-like plates in theouter circumference direction, and a plurality of the divided belt-likering plates are pasted with a prescribed interval in the pipe axisdirection of the measuring pipe, and in addition, a thickness of thebelt-like plate is a prescribed thickness, and a first gap is providedbetween the inner face of the measuring pipe and the outer circumferenceface of the cylindrical plate with openings. In case of pressure moldingthe resin lining portion, the resin to be lined can be filled easily ingaps between the measuring pipe and the lining locking frame via gapsformed by the first gap and the second gaps of the divided belt-likering plates.

According to another aspect of the present invention, there is providedan electromagnetic flow meter provided with a resin lining portion inwhich resin is lined in a measuring pipe by pressure molding, includingthe measuring pipe to flow liquid to be measured, a lining locking frameprovided in the measuring pipe composed of a cylindrical plate withopenings and a belt-like spiral plate, and the resin lining portionformed by embedding the lining locking frame. The cylindrical plate withopenings is formed by facing both end faces of a belt-like plate withopenings with a prescribed length in a circumference direction of themeasuring pipe so that the belt-like plate with openings becomes acylindrical shape concentric with the measuring pipe. The belt-likespiral plate is composed of a belt-like plate pasted spirally around theouter circumference of the cylindrical plate with openings, a thicknessof the belt-like plate is set to a prescribed thickness, a first gap isset between the inner face of the measuring pipe and the outercircumference face of the cylindrical plate with openings, and inaddition, the belt-like plate is wound around the cylindrical plate withopenings in the pipe axis direction of the measuring pipe with aprescribed interval so as to provide a spiral third gap. In case ofpressure molding the resin lining portion, the resin to be lined can befilled easily in gaps between the measuring pipe and the lining lockingframe via gaps formed by the first gap and the third gap.

According to another aspect of the present invention, there is providedan electromagnetic flow meter provided with a resin lining portion inwhich resin is lined in a measuring pipe by pressure molding, includingthe measuring pipe to flow liquid to be measured, a lining locking frameprovided in the measuring pipe composed of a cylindrical plate withopenings and a plurality of belt-like ring plates, and the resin liningportion formed by embedding the lining locking frame. The cylindricalplate with openings is formed by facing both end faces of a belt-likeplate with openings with a prescribed length in a circumferencedirection of the measuring pipe so that the belt-like plate withopenings becomes a cylindrical shape concentric with the measuring pipe.A plurality of the belt-like plates are pasted with a prescribedinterval around the outer circumference of the cylindrical plate withopenings in the pipe axis direction of the measuring pipe. Thecylindrical plate with openings is provided with not less than twocutout portions from an end which are provided alternately from the bothends in the pipe axis direction and so as to lap in the pipe axisdirection. In addition, a thickness of the belt-like ring plate is aprescribed thickness, and a first gap is provided between the inner faceof the measuring pipe and the outer circumference face of thecylindrical plate with openings. In case of pressure molding the resinlining portion, the resin to be lined can be filled easily in gapsbetween the measuring pipe and the lining locking frame via gaps formedby the first gap and fourth gaps formed by the cutout portions.

According to another aspect of the present invention, there is providedan electromagnetic flow meter provided with a resin lining portion inwhich resin is lined in a measuring pipe by pressure molding, includingthe measuring pipe to flow liquid to be measured, a lining locking frameprovided in the measuring pipe composed of divided cylindrical plateswith openings and a plurality of belt-like ring plates, and the resinlining portion formed by embedding the lining locking frame. The dividedcylindrical plates with openings are composed of not less than twobelt-like plates with openings with a prescribed length which areprovided to face both end faces of the belt-like plates with openings ofthe measuring pipe so as to form a cylindrical shape concentric with themeasuring pipe with prescribed fifth gaps in a circumference directionof belt-like plates with openings. A plurality of the belt-like ringplates are pasted with a prescribed interval around the outercircumference of the divided cylindrical plates with openings in thepipe axis direction of the measuring pipe, and a thickness of thebelt-like plate is a prescribed thickness and a first gap is providedbetween the inner face of the measuring pipe and the outer circumferenceface of the divided cylindrical plates with openings. In case ofpressure molding the resin lining portion, the resin to be lined can befilled easily in gaps formed between the measuring pipe and the lininglocking frame via the gaps formed by the first gap and the fifth gaps.

As described above, according to the present invention, as the gaps areprovided in which the lining resin material to be pressure molded aroundthe lining locking frame can easily be inpoured from any direction ofthe pipe axis direction and the direction perpendicular to the pipeaxis, an electromagnetic flow meter can be provided which can form aresin lining portion easily without generating air bubbles and residualstress in the lining resin, and without using a high level moldingtechnique such as transfer molding or injection molding.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIGS. 1A, 1B are diagrams, each showing a construction of anelectromagnetic flow meter according to a first embodiment of thepresent invention which is provided with a lining locking frame composedof a cylindrical plate with openings and divided belt-like ring plates;

FIGS. 2A, 2B are diagrams, each explaining detailed setting example ofthe divided belt-like ring plates of the lining locking frame using thecylindrical plate with openings according to the first embodiment of thepresent invention;

FIGS. 3A, 3B are diagrams, each showing a construction of anelectromagnetic flow meter according to a second embodiment of thepresent invention which is provided with a lining locking frame composedof a cylindrical plate with openings and a spiral plate;

FIGS. 4A, 4B are diagrams, each showing a construction of anelectromagnetic flow meter according to a third embodiment of thepresent invention which is provided with a lining locking frame composedof a cylindrical plate with openings having cutout portions at both endportions;

FIGS. 5A, 5B are diagrams, each showing a construction of anelectromagnetic flow meter according to a fourth embodiment of thepresent invention which is provided with a lining locking frame composedof a plurality of divided cylindrical plates with openings and belt-likering plates;

FIGS. 6A, 6B are diagrams, each showing a construction of anelectromagnetic flow meter according to another embodiment of thepresent invention which is provided with a lining locking frame composedof a plurality of divided cylindrical plates with openings having cutoutportions at an end portion and belt-like ring plates;

FIGS. 7A, 7B are diagrams, each showing a construction of anelectromagnetic flow meter according to another embodiment of thepresent invention which is provided with a lining locking frame composedof a plurality of divided cylindrical plates with openings and dividedbelt-like ring plates; and

FIGS. 8A, 8B, 8C are diagrams, each showing a construction of aconventional electromagnetic flow meter which is provided with a lininglocking frame composed of a cylindrical plate with openings andbelt-like ring plates.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views, theembodiments of this invention will be described below.

First Embodiment

FIG. 1A is a diagram to explain a construction of an electromagneticflow meter with a lining locking frame 2 of a first embodiment of thepresent invention, and FIG. 1B is a perspective view showing anappearance of the lining locking frame 2 of the first embodiment of thepresent invention.

In FIG. 1A, a side sectional view of an upper portion from a center of apipe axis of the measuring pipe 1 indicates a state before resin lining.The measuring pipe 1 to flow fluid to be measured is composed of thepipe body 1 a, a pair of the flanges 1 b provided at both the endportions of the pipe body 1 a, and a pair of the internal substancestoring boards 1 c to store loading substance such as a coil and so on,which are welded on the outer circumference of the pipe body 1 a in thepipe axis direction of the pipe body 1 a and symmetrically to the centerof the pipe axis.

In addition, a side sectional view of a lower portion from the center ofthe pipe axis of the measuring pipe 1 of FIG. 1A indicates a state afterresin lining to the measuring pipe 1. The resin lining portion 3 to belined at the inner wall of the measuring pipe 1 is made of an insulatingmaterial such as fluorine contained resin and polyurethane resin and soon. In addition, a lining locking frame 2 formed in a cylinder shape ofa thin steel plate with a plurality of openings bored is embedded bypressure forming.

A construction of the electromagnetic flow meter of the present firstembodiment is composed of the measuring pipe 1 to flow fluid to bemeasured, the lining locking frame 2 provided in the measuring pipe 1,and the resin lining portion 3 which is pressure formed by embedding thelining locking frame 2. The lining locking frame 2 is composed of thecylindrical plate with openings 2 a and a plurality of divided belt-likering plates 2 b. The cylindrical plate with openings 2 a is formed byfacing both end faces Pt, Pe of a belt-like plate with openings with aprescribed length in a circumference direction of the measuring pipe 1,so that the belt-like plate with openings becomes a cylindrical shapeconcentric with the measuring pipe 1. Each of a plurality of dividedbelt-like plates 2 b are composed of a plurality of belt-like plateswith a prescribed length L and is made ring-like around the outercircumference of the cylindrical plate with openings 2 a by providingsecond gaps Rdg between the belt-like plates in the outer circumferencedirection. And a plurality of the divided belt-like plates 2 b arepasted with a prescribed interval X1 in the pipe axis direction of themeasuring pipe 1. In addition, a thickness of the belt-like plate is seta prescribed thickness, and a first gap Rtg is provided between theinner face of the measuring pipe 1 and the outer circumference face ofthe cylindrical plate with openings 2 a.

The ring interval X1 between the divided belt-like ring plates 2 b canbe set arbitrarily to an optimum value based on a pipe diameter of themeasuring pipe 1 to be resin lined and a plate width of the dividedbelt-like ring plate 2 b, by considering the easiness to fit the lininglocking frame 2 to the inside of the measuring pipe 1 and a lockingforce required for the resin lining portion 3.

According to the construction of the first embodiment constructed asdescribed above, in case that the lining resin is pressure formed, thefirst gap Rtg in the pipe radial direction is set to the plate thicknesst of the divided belt-like ring plates 2 b between the inner face of themeasuring pipe 1 and the outer circumference face of the cylindricalplate with openings 2 a, and in addition, the second gap Rdg in the pipeaxis perpendicular direction is set by a division interval of thedivided belt-like ring plates 2 b.

The first gap Rtg and the second gap Rdg can be set to optimum valuesarbitrarily by the kind and the melting point of the lining resin, thepressure of the molding equipment, and the locking force and mechanicalstrength for the negative pressure required for the resin lining portion3.

According to the electromagnetic flow meter of the first embodimentconstructed as described above, in case that the resin lining portion 3is formed by lining in the measuring pipe 1, the resin to be lined bythe pressure molding can be pressurized from any direction of the pipeaxis direction and the direction perpendicular to the pipe axis, via thegaps formed by the first gap and the second gaps set by the dividedbelt-like ring plates 2 b, so that the resin can be easily injected witha small pressure loss.

That is, without requiring a high level pressure molding equipment suchas transfer molding in case that the resin is injected from a lot ofopenings of the cylindrical plate with openings 2 a as in theconventional, the resin can be filled easily in the gap between themeasuring pipe 1 and the lining locking frame 2 without generating airbubbles and generating stress strain only by pressurizing the meltedlining resin in the molding die, so that the electromagnetic flow meterprovided with the resin lining portion 3 which is uniform and high inquality can be provided.

In addition, it is preferable that the second gap Rdg between theadjacent divided belt-like ring plates 2 b do not overlap seen from thedirection of the outer circumference pipe axis of the measuring pipe 1as shown in FIG. 2, and the second gap Rdg and the divided length L ofthe belt-like plates are set to satisfy the relation that0.5·L≦Rdg≦1.5·L.

Second Embodiment

A second embodiment of the present invention will be described withreference to FIGS. 3A, 3B. FIGS. 3A, 3B are diagrams to explain aconstruction of an electromagnetic flow meter of a second embodiment ofthe present invention which is provided with a lining locking frame 21composed of the cylindrical plate with openings 2 a and a belt-likespiral plate 2 b 1.

Regarding the each portion of the second embodiment, the same portion ofthe each portion as in the electromagnetic flow meter shown in the firstembodiment of FIGS. 1A, 1B is shown by the same reference numeral, andthe detailed description thereof is omitted. The point in the secondembodiment different from the first embodiment is that the lininglocking frame 21 is composed using the belt-like spiral plate 2 b 1, inplace of the divided belt-like ring plates 2 b of the lining lockingframe 2.

A construction of the lining locking frame 21 is composed of thecylindrical plate with openings 2 a formed by facing both end faces Pt,Pe of a belt-like plate with openings with a prescribed length in thecircumference direction of the measuring pipe 1 so that the belt-likeplate with openings becomes a cylindrical shape concentric with themeasuring pipe 1 in the measuring pipe 1, and a belt-like spiral plate 2b 1 composed of a belt-like plate pasted spirally around the outercircumference of the cylindrical plate with openings 2 a. Here, athickness of the belt-like plate is set to a prescribed thickness, andthe first gap Rtg is set between the inner face of the measuring pipe 1and the outer circumference face of the cylindrical plate with openings2 a. The belt-like plate is wound around the cylindrical plate withopenings 2 a in the pipe axis direction of the measuring pipe 1 with aprescribed spiral pitch (an interval X2) so as to provide a third gapS_(Rtg-X2).

The spiral pitch X2 can be set arbitrarily to an optimum value based ona pipe diameter of the measuring pipe 1 to be resin lined and a platewidth of the belt-like plate, by considering the easiness to fit thelining locking frame 21 to the inside of the measuring pipe 1 and alocking force and the mechanical strength required for the resin liningportion 3.

According to the electromagnetic flow meter of the second embodimentconstructed as described above, in case of the resin lining portion 3 isformed by lining in the measuring pipe 1, the resin to be lined by thepressure molding can be pressurized along the belt-like spiral plate 2 b1 via the gaps formed by the first gap and the third gap set by thebelt-like spiral plate 2 b 1, so that the resin can be easily injectedwith a small pressure loss.

Accordingly, without requiring a high level pressure molding equipmentsuch as transfer molding in case that the resin is injected from a lotof openings of the cylindrical plate with openings 2 a as in theconventional, the resin can be filled easily in the gap between themeasuring pipe 1 and the lining locking frame 21 without generating airbubbles and generating stress strain only by pressurizing the meltedlining resin in the molding die, so that the electromagnetic flow meterprovided with the lining portion 3 which is uniform and high in qualitycan be provided.

Third Embodiment

A third embodiment of the present invention will be described withreference to FIGS. 4A, 4B. FIGS. 4A, 4B are diagrams to explain aconstruction of an electromagnetic flow meter according to a thirdembodiment of the present invention which is provided with a lininglocking frame 22 composed of a cylindrical plate with openings 2 a 1 andbelt-like ring plates 2 b 2.

Regarding the each portion of the third embodiment, the same portion ofthe each portion as in the electromagnetic flow meter shown in the firstembodiment of FIGS. 1A, 1B is shown by the same reference numeral, andthe detailed description thereof is omitted. The point in the thirdembodiment different from the first embodiment is that the lininglocking frame 22 is composed of the cylindrical plate with openings 2 a1 formed by providing cutout portions at both end portions of thecylindrical plate with openings 2 a and the belt-like ring plates 2 b 2,in place of the lining locking frame 2 composed of the cylindrical platewith openings 2 a and the divided belt-like ring plates 2 b.

The lining locking frame 22 is provided with the cylindrical plate withopenings 2 a 1 formed by facing both end faces Pt, Pe of a belt-likeplate with openings with a prescribed length in the circumferencedirection of the measuring pipe 1 so that the belt-like plate withopenings becomes a cylindrical shape concentric with the measuring pipe1, and a plurality of the belt-like ring plates 2 b 2 composed ofbelt-like plates pasted around the outer circumference of thecylindrical plate with openings 2 a 1 in the pipe axis direction of themeasuring pipe 1 with a prescribed interval.

And in the cylindrical plate with openings 2 a 1, not less than twocutout portions Pcg are provided from an end which are providedalternately from the both ends in the pipe axis direction and so as tolap in the pipe axis direction, and in addition, a thickness of thebelt-like ring plates 2 b 2 is set a prescribed thickness and the firstgap Rtg is provided between the inner face of the measuring pipe 1 andthe outer circumference face of the cylindrical plate with openings 2 a1.

According to the electromagnetic flow meter of the third embodimentconstructed as described above, in case that the resin lining portion 3is formed by lining in the measuring pipe 1, the resin to be lined bythe pressure molding can be easily injected in the gap between themeasuring pipe 1 and the lining locking frame 22, via the gaps formed bythe first gap Rtg and the fourth gaps by the cutout portions Pcg.

The first gap Rtg and the fourth gap Pcg can be set to optimum valuesarbitrarily by the kind and the melting point of the lining resin, thepressure of the molding equipment, the locking force and mechanicalstrength for the negative pressure required for the resin lining portion3.

Accordingly, without requiring a high level pressure molding equipmentsuch as transfer molding in case that the resin is injected from a lotof openings of the cylindrical plate with openings as in theconventional, the resin can be filled easily in the gap between themeasuring pipe 1 and the lining locking frame 22 without generating airbubbles and generating stress strain only by pressurizing the meltedlining resin in the molding die, so that the electromagnetic flow meterprovided with the resin lining portion 3 which is uniform and high inquality can be provided.

Fourth Embodiment

A fourth embodiment of the present invention will be described withreference to FIGS. 5A, 5B. FIGS. 5A, 5B are diagrams to explain aconstruction of an electromagnetic flow meter according to a fourthembodiment of the present invention which is provided with a lininglocking frame 23 composed of a plurality of divided cylindrical platewith openings 2 a 2 and belt-like ring plates 2 b 2.

Regarding the each portion of the fourth embodiment, the same portion ofthe each portion as in the electromagnetic flow meter shown in the firstembodiment of FIGS. 1A, 1B is shown by the same reference numeral, andthe detailed description thereof is omitted. The point in the fourthembodiment different from the first embodiment is that the lininglocking frame 23 is composed of a plurality of the divided cylindricalplates with openings 2 a 2 and the belt-like ring plates 2 b 2, in placeof the lining locking frame 2 composed of the cylindrical plate withopenings 2 a and the divided belt-like ring plates 2 b.

A construction of the lining locking frame 23 is composed of the dividedcylindrical plate with openings 2 a 2 formed by providing prescribedfifth gaps Pdg between both end faces of not less than belt-like platewith openings with a prescribed length in the circumference direction ofthe measuring pipe 1 so that the belt-like plates with openings form acylinder concentric with the measuring pipe 1, and a plurality of thebelt-like ring plates 2 b 2 composed of belt-like plates pasted aroundthe outer circumference of the divided cylindrical plates with openings2 a 2 in the pipe axis direction of the measuring pipe 1 in a prescribedinterval X3. In addition, a thickness of the belt-like plate is set aprescribed thickness, and the first gap Rtg is provided between theinner face of the measuring pipe 1 and the outer circumference face ofthe divided cylindrical plates with openings 2 a 2.

The fitting end faces Pt, Pe of the divided cylindrical plates withopenings 2 a 2 are formed preliminarily so that the divided cylindricalplates with openings 2 a 2 has a diameter which can be fitted to theinner wall face of the measuring pipe 1 as in the first embodiment, anda few of a plurality the of belt-like ring plates 2 b 2 are spot weldedto the inner circumference face of the measuring pipe 1.

In addition, the first gap Rtg and the fifth gap Pdg can be set tooptimum values arbitrarily by the kind and the melting point of thelining resin, the pressure of the molding equipment, the locking forceand mechanical strength for the negative pressure required for the resinlining portion 3.

According to the electromagnetic flow meter of the fourth embodimentconstructed as described above, in case that the resin lining portion 3is formed by lining in the measuring pipe 1, the resin to be lined bythe pressure molding can be easily injected in the gap between themeasuring pipe 1 and the lining locking frame 23, via the gap formed bythe first gap Rtg and the fifth gaps Pdg.

Accordingly, without requiring a high level pressure forming equipmentsuch as transfer molding in case that the resin is injected from a lotof openings of the cylindrical plate with openings as in theconventional, the resin can be filled easily in the gap between themeasuring pipe 1 and the lining locking frame 23 without generating airbubbles and generating stress strain only by pressurizing the meltedlining resin in the molding die, so that the electromagnetic flow meterprovided with the resin lining portion 3 which is uniform and high inquality can be provided.

In addition, as shown in FIGS. 6A, 6B, in place of the dividedcylindrical plates with openings 2 a 2 of the lining locking frame 23, alining locking frame 24 can be constructed as shown in FIGS. 6A, 6Busing divided cylindrical plates with openings 2 a 3, each provided withnot less than two cutout portions with a length to lap in the pipe axisdirection alternately from the both ends of the pipe axis direction.

In addition, as shown in FIGS. 7A, 7B, in place of the belt-like ringplates 2 b 2 of the lining locking frame 23, a lining locking frame 25can be constructed using divided belt-like plates 2 b with the secondgaps Rdg which are formed by dividing in the outer circumferencedirection of the measuring pipe 1 by a prescribed length and aprescribed interval. Here, the second gap Rdg between the adjacentdivided belt-like ring plates 2 b do not overlap in the direction of theouter circumference pipe axis of the measuring pipe 1, and the secondgap Rdg and the divided length L of the divided belt-like ring plates 2b satisfy the relation that 0.5·L≦Rdg≦1.5·L.

The present invention is not limited to the above-described embodimentsat all. The lining locking frame may be used in which the gap in whichthe lining resin to be pressure molded can be pressurized with a lowpressure loss is set by the cylindrical plate with openings and theplate thicknesses of the belt-like plates provided around the outercircumference of the cylindrical plate with openings, and which isprovided with the locking force and mechanical strength to withstand thenegative pressure provision required for the measuring pipe 1. And thepresent invention can be practiced in various modifications within thescope without departing the gist of the present invention.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

1. An electromagnetic flow meter provided with a lining portion in whichresin is lined in a measuring pipe by pressure molding, comprising: themeasuring pipe to flow liquid to be measured; a lining locking frameprovided in the measuring pipe, composed of a cylindrical plate withopenings and a plurality of divided belt-like ring plates; and the resinlining portion formed by embedding the lining locking frame; wherein thecylindrical plate with openings is formed by facing both end faces of abelt-like plate with openings with a prescribed length in acircumference direction of the measuring pipe so that the belt-likeplate with openings becomes a cylindrical shape concentric with themeasuring pipe; wherein each of the divided belt-like ring plates iscomposed of a plurality of belt-like plates with a prescribed length andis made ring-like around the outer circumference of the cylindricalplate with openings by providing second gaps between the belt-likeplates in the outer circumference direction, and a plurality of thedivided belt-like ring plates are pasted with a prescribed interval inthe pipe axis direction of the measuring pipe, and in addition, athickness of the belt-like plate is a prescribed thickness, and a firstgap is provided between the inner face of the measuring pipe and theouter circumference face of the cylindrical plate with openings; andwherein in case of pressure molding the resin lining portion, the resinto be lined can be filled easily in gaps between the measuring pipe andthe lining locking frame via gaps formed by the first gap and the secondgaps of the divided belt-like ring plates.
 2. The electromagnetic flowmeter as recited in claim 1, wherein: a plurality of the dividedbelt-like ring plates are provided so that the second gaps of theadjacent divided belt-like ring plates do not overlap in the directionof the outer circumference pipe axis of the measuring pipe, and thesecond gap and the divided length of the belt-like plate satisfy therelation that 0.5·L≦Rdg≦1.5·L, here, the second gap is Rdg and thedivided length of the belt-like plate is L.
 3. An electromagnetic flowmeter provided with a resin lining portion in which resin is lined in ameasuring pipe by pressure molding, comprising: the measuring pipe toflow liquid to be measured; a lining locking frame provided in themeasuring pipe composed of a cylindrical plate with openings and abelt-like spiral plate; and the resin lining portion formed by embeddingthe lining locking frame; wherein the cylindrical plate with openings isformed by facing both end faces of a belt-like plate with openings witha prescribed length in a circumference direction of the measuring pipeso that the belt-like plate with openings becomes a cylindrical shapeconcentric with the measuring pipe; wherein the belt-like spiral plateis composed of a belt-like plate pasted spirally around the outercircumference of the cylindrical plate with openings, a thickness of thebelt-like plate is set to a prescribed thickness, a first gap is setbetween the inner face of the measuring pipe and the outer circumferenceface of the cylindrical plate with openings, and in addition, thebelt-like plate is wound around the cylindrical plate with openings inthe pipe axis direction of the measuring pipe with a prescribed intervalso as to provide a spiral third gap; and wherein in case of pressuremolding the resin lining portion, the resin to be lined can be filledeasily in gaps between the measuring pipe and the lining locking framevia gaps formed by the first gap and the third gap.
 4. Anelectromagnetic flow meter provided with a resin lining portion in whichresin is lined in a measuring pipe by pressure molding, comprising: themeasuring pipe to flow liquid to be measured; a lining locking frameprovided in the measuring pipe composed of a cylindrical plate withopenings and a plurality of belt-like ring plates; and the resin liningportion formed by embedding the lining locking frame; wherein thecylindrical plate with openings is formed by facing both end faces of abelt-like plate with openings with a prescribed length in acircumference direction of the measuring pipe so that the belt-likeplate with openings becomes a cylindrical shape concentric with themeasuring pipe; wherein a plurality of the belt-like plates are pastedwith a prescribed interval around the outer circumference of thecylindrical plate with openings in the pipe axis direction of themeasuring pipe; wherein the cylindrical plate with openings is providedwith not less than two cutout portions from an end which are providedalternately from the both ends in the pipe axis direction and so as tolap in the pipe axis direction; wherein in addition, a thickness of thebelt-like ring plate is a prescribed thickness, and a first gap isprovided between the inner face of the measuring pipe and the outercircumference face of the cylindrical plate with openings; and whereinin case of pressure molding the resin lining portion, the resin to belined can be filled easily in gaps between the measuring pipe and thelining locking frame via gaps formed by the first gap and fourth gapsformed by the cutout portions.
 5. An electromagnetic flow meter providedwith a resin lining portion in which resin is lined in a measuring pipeby pressure molding, comprising: the measuring pipe to flow liquid to bemeasured; a lining locking frame provided in the measuring pipe composedof divided cylindrical plates with openings and a plurality of belt-likering plates; and the resin lining portion formed by embedding the lininglocking frame; wherein the divided cylindrical plates with openings arecomposed of not less than two belt-like plates with openings with aprescribed length which are provided to face both end faces of thebelt-like plates with openings of the measuring pipe so as to form acylindrical shape concentric with the measuring pipe with prescribedfifth gaps in a circumference direction of belt-like plates withopenings; wherein a plurality of the belt-like ring plates are pastedwith a prescribed interval around the outer circumference of the dividedcylindrical plates with openings in the pipe axis direction of themeasuring pipe, and a thickness of the belt-like plate is a prescribedthickness and a first gap is provided between the inner face of themeasuring pipe and the outer circumference face of the dividedcylindrical plates with openings; and wherein in case of pressuremolding the resin lining portion, the resin to be lined can be filledeasily in gaps formed between the measuring pipe and the lining lockingframe via the gaps formed by the first gap and the fifth gaps.
 6. Theelectromagnetic flow meter as recited in claim 5, wherein: each of thebelt-like ring plates is composed of divided belt-like ring plates witha prescribed length and with a second gap by dividing with a prescribedinterval in the outer circumference direction of the measuring pipe; anda plurality of the divided belt-like ring plates are provided so thatthe second gaps of the adjacent divided belt-like ring plates do notoverlap in the direction of the outer circumference pipe axis of themeasuring pipe, and the second gap and the divided length of thebelt-like plate satisfy the relation that 0.5·L≦Rdg≦1.5·L, here, thesecond gap is Rdg and the divided length of the belt-like plate is L.